Uptake and resource allocation of ammonium and nitrate in temperate seagrasses Posidonia and Amphibolis

Nayar, Sasi; Collings, Greg; Miller, David J.; Bryars, Simon; Cheshire, Anthony

doi:10.1016/j.marpolbul.2010.04.018

Cited by 15 publications

(14 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pore water samples were also collected in triplicate using the air-stone based pore water sampler described in Nayar et al . 18 . The 60 mL syringe with which the pore water sample was collected was capped upon collection underwater, with the sample processed immediately on the boat.…”

Section: Methodsmentioning

confidence: 99%

“…Various studies have identified ammonium (NH 4 + ), nitrate (NO 3 − ) and nitrite (NO 2 − ) as the largest sources of nitrogen for seagrass 13 , 18 . There is limited knowledge on uptake rates of organic nitrogen sources in seagrass beds, but evidence in the literature indicates they are relatively insignificant if inorganic nitrogen is prevalent 19 , 20 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Nayar

Loo

Tanner

et al. 2018

Sci Rep

Self Cite

View full text Add to dashboard Cite

The dominant seagrass in Port Phillip Bay (PPB), Australia, Zostera nigricaulis, declined between 2000 and 2011, coinciding with the ‘Millennium drought’ that ended in 2009. These seagrasses are nitrogen-limited, underpinning the need to develop nitrogen budgets for better ecosystem management. Environmentally realistic measurements of specific uptake rates and resource allocation were undertaken to develop nitrogen budgets and test the hypothesis that the above-ground and below-ground compartments are able to re-mobilise ammonium and nitrate through uptake, translocation and assimilation to adapt to varying levels of nitrogen in the ecosystem. Uptake of 15N labelled ammonium and nitrate by above- and below-ground seagrass biomass, epiphytes and phytoplankton was quantified in chambers in situ. Preferential uptake of ammonium over nitrate was observed, where the uptake rate for nitrate was about one sixth of that for ammonium. Epiphytes and phytoplankton also registered an increased affinity for ammonium over nitrate. Translocation experiments demonstrated the uptake by both the above-ground and below-ground biomass, respectively from the water column and pore water, and subsequent translocation to the opposite compartment. Acropetal translocation (below- to above-ground biomass) was more prevalent than basipetal translocation. This is a unique outcome given basipetal translocation has been widely reported for Zostera by other researchers.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Nayar

Loo

Tanner

et al. 2018

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Leaf material was processed and measured for total nitrogen content and atom% 15 N according to method described in Takahashi et al 45 . Uptake rates (μmol N g −1 dry weight h −1 ) of 15 NO 3 − were calculated following equations outlined in Nayar et al 23 . The atom% 15 N of 15 N enriched seawater was calculated based on the amount of atom% added and background DIN concentrations (assumed to reflect 15 N concentration of atmospheric N ~ 0.37 atom% 15 N).…”

Section: Methodsmentioning

confidence: 99%

“…Both uptake and assimilation are inducible processes that may reflect instantaneous nitrogen demand in the plant 22 . For seagrasses, inorganic nitrate and ammonium are considered the most significant sources of nitrogen, supplying over 90% of externally acquired nitrogen 22 23 . Sediment pore-water can potentially supply the majority of nitrogen for seagrass as the sediment contains higher concentrations of nitrogen than the water column does, but seagrasses will rapidly absorb DIN from the water column 24 .…”

mentioning

confidence: 99%

Nitrate fertilisation does not enhance CO2 responses in two tropical seagrass species

Vogel

Collier

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Seagrasses are often considered “winners” of ocean acidification (OA); however, seagrass productivity responses to OA could be limited by nitrogen availability, since nitrogen-derived metabolites are required for carbon assimilation. We tested nitrogen uptake and assimilation, photosynthesis, growth, and carbon allocation responses of the tropical seagrasses Halodule uninervis and Thalassia hemprichii to OA scenarios (428, 734 and 1213 μatm pCO2) under two nutrients levels (0.3 and 1.9 μM NO3−). Net primary production (measured as oxygen production) and growth in H. uninervis increased with pCO2 enrichment, but were not affected by nitrate enrichment. However, nitrate enrichment reduced whole plant respiration in H. uninervis. Net primary production and growth did not show significant changes with pCO2 or nitrate by the end of the experiment (24 d) in T. hemprichii. However, nitrate incorporation in T. hemprichii was higher with nitrate enrichment. There was no evidence that nitrogen demand increased with pCO2 enrichment in either species. Contrary to our initial hypothesis, nutrient increases to levels approximating present day flood plumes only had small effects on metabolism. This study highlights that the paradigm of increased productivity of seagrasses under ocean acidification may not be valid for all species under all environmental conditions.

show abstract

“…Seagrasses are marine angiosperms that provide important ecosystem functions and services (Hemminga and Duarte 2000, Cullen-Unsworth and Unsworth 2013, Nordlund et al 2016, Nordlund et al 2018. For example, seagrass can attenuate waves, stabilize sediments, reduce erosion, sequester carbon, take up land-derived nutrients and provide habitat for epiphytes, invertebrates and fish (Ward et al 1984, Koch and Gust 1999, Holmer et al 2004, Nayar et al 2010, Tuya et al 2011, Fourqurean et al 2012, Thomsen et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Seagrass beds provide habitat for crabs, shrimps and fish in two estuaries on the South Island of New Zealand

Thomsen

Moser

Pullen

et al. 2020

Preprint

View full text Add to dashboard Cite

SummarySeagrasses are marine angiosperms that potentially provide habitat for crabs, shrimps and fish. However, these types of data are lacking for the seagrass species (Zostera muelleri/rimurēhia) that inhabit intertidal estuaries on the South Island of New Zealand.Abundances of crabs, shrimps and fish were therefore quantified from 361 non-destructive seine tows done in seagrass beds and bare mudflats in Duvauchelle bay and two sites in the Avon-Heathcote/Ihutai estuary between October 2019 and February 2020.A total of 2549 crabs, 5824 shrimps and 1149 fish (75% were juvenile flounders) were identified and counted in the seine-net and immediately released back in healthy condition to the exact location from where they were caught.Only few seagrass leaves were caught in the net and these leaves may have been previously uprooted drift fragments. The instant catch-and-release methodology therefore leaves, literally, nothing but a footprint.More fish taxa, including two species of pipefish, were found in seagrass beds in Duvauchelle bay than in the Avon-Heathcote estuary. Fish (minus juvenile flounders) were also more abundant in these seagrass beds. Furthermore, juvenile flounders and shrimps were more abundant in Duvauchelle bay compared to the Avon-Heathcote estuary, but were found in similar abundances in seagrass beds and on bare flats.It is possible that more fish were found in Duvauchelle seagrass beds because these beds have adjacent deeper areas, and may have high connectivity to seagrass beds in nearby bays. This hypothesis should be tested by sampling more seagrass beds in different types of estuaries and bays.By contrast, crabs were more abundant in the Avon-Heathcote estuary, where spider crabs were most abundant in the seagrass beds, but other crabs were found in similar abundances in seagrass beds and bare habitat. We hypothesize that crab abundances were higher in the Avon-Heathcote estuary because of lower fish predation pressure and/or larger populations of prey like mollusc and polychaetes.Our results suggests that (a) superficially similar Zostera beds in relatively close proximity can provide very different habitat values for fish and crustaceans, (b) seagrass beds with higher diversity and abundances of fish may be prioritized in conservation and management (assuming other important ecosystem functions are similar between beds), and (c) that pipefish may be useful indicator organisms, representing healthy, extensive, dense and connected seagrass beds.Abstract Figure

show abstract

Uptake and resource allocation of ammonium and nitrate in temperate seagrasses Posidonia and Amphibolis

Cited by 15 publications

References 42 publications

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Nitrogen acquisition and resource allocation strategies in temperate seagrass Zostera nigricaulis: Uptake, assimilation and translocation processes

Nitrate fertilisation does not enhance CO2 responses in two tropical seagrass species

Seagrass beds provide habitat for crabs, shrimps and fish in two estuaries on the South Island of New Zealand

Contact Info

Product

Resources

About